The Buderus GC144 boiler is a compact, easy to install boiler with all the features and benefits Buderus customers have come to expect. NEW! Efficiency ratings of 85% on all models! Stainless Steel Corrosion Resistant Premix Burners GL-180M Flexible Cast Iron Electronic Ignition Side Piping Design for Convenient Boiler Retrofit Installation 3 Models with Inputs from 74,000 to 132,500 BTU/Hr